SOLUTION: Mark took three tests. His grades were 74, 81 and 70. what grade must he get on the fourth test to receive an 80 average on the four tests?

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Question 353446: Mark took three tests. His grades were 74, 81 and 70. what grade must he get on the fourth test to receive an 80 average on the four tests?
Answer by rfer(16322) About Me  (Show Source):
You can put this solution on YOUR website!
(74+81+70+x)/4=80
225+x=80*4
225+x=320
x=95